Why musk this be so confusing?

Good evening!

I (20m) am still quite a novice on exploring my passion for fragrance, particularly those of the vintage category.

On this journey I have been attempting to train my nose. I would like to have a deeper understanding on identifying each individual nuance in a scent.

I have come to fall in love with animalics and fougere adjacent fragrance, to name a few.

Upon beginning this journey, I assumed “musks” were in the animalic category. Over the course of testing various fragrances, some, especially in their dry-downs, have had a similar note that has frustrated me. It has a frisky, almost “cola-like” aroma. The through line with these fragrances was musk in the dry down.

I decided to do some deeper research on musks. I was surprised to find that they can come from animals and plants. Because of current regulations, plants or synthetic origin is more likely. Now, I realize there are hundreds of different musks, so bear with me.

A couple questions:

How does your nose identify musk?

Why do we identify musks so closely with animals if they can come from seemingly everywhere, and hardly from animals?

Am I smelling something else in the unfavorable dry-downs that may not be musks, considering I enjoy authentic civet, musk deer, and castoreum?

Thank you for your time :)